Reduction type polycarboxylic acid water reducer as well as preparation method and application thereof

Abstract

The invention relates to a reduction type polycarboxylic acid water reducer as well as a preparation method and application thereof. The water reducer is prepared from the following raw materials: an unsaturated polyether macromonomer, an unsaturated acid monomer and a reduction type functional monomer, and further comprises an initiator, a chain transfer agent and deionized water, wherein the molar ratio of the unsaturated polyether macromonomer to the unsaturated acid monomer to the reduction type functional monomer is 1: (4-6): (2-5). Isopentenyl polyoxyethylene ether, the unsaturated acid monomer, the reduction type functional monomer, the chain transfer agent, the initiator and the deionized water are adopted, and the polycarboxylic acid water reducer with high water-reducing rate and excellent shrinkage-reducing performance is prepared by a free radical copolymerization method through molecular structure design. The water reducer is used for reducing the shrinkage rate of a cementing material, and the mixing amount of the water reducer in the cementing material is 0.1-0.2% of the mass of the cementing material. Compared with the prior art, the reduction type polycarboxylic acid water reducer has the advantages of low doping amount, excellent reduction effect, simple synthesis process, energy saving, environmental protection and the like.

Description

technical field

[0001] The invention relates to the field of concrete admixtures, in particular to a shrinkage-reducing polycarboxylate water reducer and its preparation method and application. Background technique

[0002] The cracking caused by the volume shrinkage of concrete seriously affects the safety, durability and aesthetics of concrete structures. From bridges, roads and other transportation facilities to coastal seaport engineering structures, from civil buildings, commercial buildings to industrial buildings, the impact of cracking problems is very extensive. Therefore, reducing the volume shrinkage of concrete and controlling the internal defects of concrete are very important to improve the application performance of concrete.

[0003] At present, in order to deal with the shrinkage of concrete in engineering, in addition to taking measures such as adding structural steel bars, setting construction joints, reducing the temperature difference between the inside...

Examples

preparation example Construction

[0047] The preparation method of shrinkage-reducing polycarboxylate water-reducer comprises the following steps:

[0048] (1) by mass ratio, take reducing component, chain transfer agent and deionized water and mix uniformly, be made into A solution;

[0049] (2) According to the molar ratio, take the unsaturated acid monomer and the shrinkage-reducing functional monomer and mix them uniformly to form a B solution;

[0050] (3) According to the mass ratio, add unsaturated polyether macromonomer and deionized water into the reaction vessel, stir, so that the unsaturated polyether monomer is dissolved in deionized water; the stirring rate of the stirrer is 200-700rad / min , preferably 400rad / min.

[0051] (4) According to the mass ratio, add the initiator oxidation component in the reaction vessel, then add the A solution and the B solution in the reaction vessel, and start the polymerization reaction, and the whole polymerization reaction continues under the conditions of the w...

Embodiment 1

[0054] A shrinkage-reducing polycarboxylate water-reducer, laboratory synthesis of 500 parts by weight of mother liquor with a solid content of 40.3% The specific operation steps are as follows:

[0055] Fix the four-necked flask on an iron stand, immerse the bottom end in a constant temperature water bath, adjust the temperature of the water bath to 45°C to ensure that the entire polymerization process is carried out under this temperature condition, put a thermometer on the four-necked flask, stir A device, a constant pressure funnel, and a wooden stopper inserted into the conduits of liquid A and liquid B, and adjust the height of the four-neck flask to ensure that the stirrer can work normally.

[0056] The molar ratio of polyether macromonomer TPEG-2800, unsaturated acid monomer AA and shrinkage functional monomer BA is 1:5:4. Add 152.51 parts by weight of TPEG-2800 and 150 parts by weight of deionized water into the four-neck flask, start the stirrer, and adjust the spee...

Embodiment 2

[0060] A shrinkage-reducing polycarboxylate water-reducer, 500 parts by weight of mother liquor with a solid content of 40.3% synthesized in the laboratory. The specific operation steps are as follows: fix the four-necked flask on the iron stand, immerse the bottom end in a constant temperature water bath, Adjust the temperature of the water bath to 45°C to ensure that the entire polymerization process is carried out under this temperature condition. Put a thermometer, a stirrer, a constant pressure funnel and a wooden stopper connected to the conduits of A liquid and B liquid on the four-necked flask, and adjust the four-necked flask. The height of the flask ensures that the stirrer can work normally.

[0061] The molar ratio of polyether macromonomer TPEG-2800, unsaturated acid monomer AA and shrinkage functional monomer BA is 1:5:2. Add 163.93 parts by weight of TPEG-2800 and 150 parts by weight of deionized water into the four-neck flask, start the stirrer, and adjust the ...

technical field

[0001] The invention relates to the field of concrete admixtures, in particular to a shrinkage-reducing polycarboxylate water reducer and its preparation method and application. Background technique

[0002] The cracking caused by the volume shrinkage of concrete seriously affects the safety, durability and aesthetics of concrete structures. From bridges, roads and other transportation facilities to coastal seaport engineering structures, from civil buildings, commercial buildings to industrial buildings, the impact of cracking problems is very extensive. Therefore, reducing the volume shrinkage of concrete and controlling the internal defects of concrete are very important to improve the application performance of concrete.

[0003] At present, in order to deal with the shrinkage of concrete in engineering, in addition to taking measures such as adding structural steel bars, setting construction joints, reducing the temperature difference between the inside...

Examples

preparation example Construction

[0047] The preparation method of shrinkage-reducing polycarboxylate water-reducer comprises the following steps:

[0048] (1) by mass ratio, take reducing component, chain transfer agent and deionized water and mix uniformly, be made into A solution;

[0049] (2) According to the molar ratio, take the unsaturated acid monomer and the shrinkage-reducing functional monomer and mix them uniformly to form a B solution;

[0050] (3) According to the mass ratio, add unsaturated polyether macromonomer and deionized water into the reaction vessel, stir, so that the unsaturated polyether monomer is dissolved in deionized water; the stirring rate of the stirrer is 200-700rad / min , preferably 400rad / min.

[0051] (4) According to the mass ratio, add the initiator oxidation component in the reaction vessel, then add the A solution and the B solution in the reaction vessel, and start the polymerization reaction, and the whole polymerization reaction continues under the conditions of the w...

Embodiment 1

[0054] A shrinkage-reducing polycarboxylate water-reducer, laboratory synthesis of 500 parts by weight of mother liquor with a solid content of 40.3% The specific operation steps are as follows:

[0055] Fix the four-necked flask on an iron stand, immerse the bottom end in a constant temperature water bath, adjust the temperature of the water bath to 45°C to ensure that the entire polymerization process is carried out under this temperature condition, put a thermometer on the four-necked flask, stir A device, a constant pressure funnel, and a wooden stopper inserted into the conduits of liquid A and liquid B, and adjust the height of the four-neck flask to ensure that the stirrer can work normally.

[0056] The molar ratio of polyether macromonomer TPEG-2800, unsaturated acid monomer AA and shrinkage functional monomer BA is 1:5:4. Add 152.51 parts by weight of TPEG-2800 and 150 parts by weight of deionized water into the four-neck flask, start the stirrer, and adjust the spee...

Embodiment 2

[0060] A shrinkage-reducing polycarboxylate water-reducer, 500 parts by weight of mother liquor with a solid content of 40.3% synthesized in the laboratory. The specific operation steps are as follows: fix the four-necked flask on the iron stand, immerse the bottom end in a constant temperature water bath, Adjust the temperature of the water bath to 45°C to ensure that the entire polymerization process is carried out under this temperature condition. Put a thermometer, a stirrer, a constant pressure funnel and a wooden stopper connected to the conduits of A liquid and B liquid on the four-necked flask, and adjust the four-necked flask. The height of the flask ensures that the stirrer can work normally.

[0061] The molar ratio of polyether macromonomer TPEG-2800, unsaturated acid monomer AA and shrinkage functional monomer BA is 1:5:2. Add 163.93 parts by weight of TPEG-2800 and 150 parts by weight of deionized water into the four-neck flask, start the stirrer, and adjust the ...

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